/*******************************************************************************
 * Copyright 2011 Google Inc. All Rights Reserved.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.plusthelink.samples.apps.marketplace.openid;

import com.google.step2.discovery.HostMeta;
import com.google.step2.discovery.HostMetaException;
import com.google.step2.discovery.HostMetaFetcher;

/**
 * Simple fetcher to serially try different host-meta fetching strategies, returning the
 * first one to find data.
 */
public class SerialHostMetaFetcher implements
		com.google.step2.discovery.HostMetaFetcher {
	HostMetaFetcher[] fetchers;

	public SerialHostMetaFetcher(HostMetaFetcher... fetchers) {
		this.fetchers = fetchers;
	}

	public HostMeta getHostMeta(String domain) throws HostMetaException {
		for (int i = 0; i < fetchers.length; ++i) {
			HostMeta info = fetchers[i].getHostMeta(domain);
			if (isValidHostMeta(info)) {
				return info;
			}
		}
		return null;
	}

	protected boolean isValidHostMeta(HostMeta info) {
		if (info != null && !info.getLinks().isEmpty()) {
			return true;
		} else {
			return false;
		}
	}
}
